Filename | /home/leont/perl5/perlbrew/perls/perl-5.32.0/lib/5.32.0/feature.pm |
Statements | Executed 68 statements in 47µs |
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1 | 1 | 1 | 22µs | 22µs | __common | feature::
1 | 1 | 1 | 2µs | 24µs | import | feature::
0 | 0 | 0 | 0s | 0s | croak | feature::
0 | 0 | 0 | 0s | 0s | unimport | feature::
0 | 0 | 0 | 0s | 0s | unknown_feature | feature::
0 | 0 | 0 | 0s | 0s | unknown_feature_bundle | feature::
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1 | # -*- buffer-read-only: t -*- | ||||
2 | # !!!!!!! DO NOT EDIT THIS FILE !!!!!!! | ||||
3 | # This file is built by regen/feature.pl. | ||||
4 | # Any changes made here will be lost! | ||||
5 | |||||
6 | package feature; | ||||
7 | |||||
8 | 1 | 300ns | our $VERSION = '1.58'; | ||
9 | |||||
10 | 1 | 3µs | our %feature = ( | ||
11 | fc => 'feature_fc', | ||||
12 | isa => 'feature_isa', | ||||
13 | say => 'feature_say', | ||||
14 | state => 'feature_state', | ||||
15 | switch => 'feature_switch', | ||||
16 | bitwise => 'feature_bitwise', | ||||
17 | indirect => 'feature_indirect', | ||||
18 | evalbytes => 'feature_evalbytes', | ||||
19 | signatures => 'feature_signatures', | ||||
20 | current_sub => 'feature___SUB__', | ||||
21 | refaliasing => 'feature_refaliasing', | ||||
22 | postderef_qq => 'feature_postderef_qq', | ||||
23 | unicode_eval => 'feature_unieval', | ||||
24 | declared_refs => 'feature_myref', | ||||
25 | unicode_strings => 'feature_unicode', | ||||
26 | ); | ||||
27 | |||||
28 | 1 | 4µs | our %feature_bundle = ( | ||
29 | "5.10" => [qw(indirect say state switch)], | ||||
30 | "5.11" => [qw(indirect say state switch unicode_strings)], | ||||
31 | "5.15" => [qw(current_sub evalbytes fc indirect say state switch unicode_eval unicode_strings)], | ||||
32 | "5.23" => [qw(current_sub evalbytes fc indirect postderef_qq say state switch unicode_eval unicode_strings)], | ||||
33 | "5.27" => [qw(bitwise current_sub evalbytes fc indirect postderef_qq say state switch unicode_eval unicode_strings)], | ||||
34 | "all" => [qw(bitwise current_sub declared_refs evalbytes fc indirect isa postderef_qq refaliasing say signatures state switch unicode_eval unicode_strings)], | ||||
35 | "default" => [qw(indirect)], | ||||
36 | ); | ||||
37 | |||||
38 | 1 | 500ns | $feature_bundle{"5.12"} = $feature_bundle{"5.11"}; | ||
39 | 1 | 100ns | $feature_bundle{"5.13"} = $feature_bundle{"5.11"}; | ||
40 | 1 | 100ns | $feature_bundle{"5.14"} = $feature_bundle{"5.11"}; | ||
41 | 1 | 400ns | $feature_bundle{"5.16"} = $feature_bundle{"5.15"}; | ||
42 | 1 | 200ns | $feature_bundle{"5.17"} = $feature_bundle{"5.15"}; | ||
43 | 1 | 100ns | $feature_bundle{"5.18"} = $feature_bundle{"5.15"}; | ||
44 | 1 | 100ns | $feature_bundle{"5.19"} = $feature_bundle{"5.15"}; | ||
45 | 1 | 100ns | $feature_bundle{"5.20"} = $feature_bundle{"5.15"}; | ||
46 | 1 | 100ns | $feature_bundle{"5.21"} = $feature_bundle{"5.15"}; | ||
47 | 1 | 100ns | $feature_bundle{"5.22"} = $feature_bundle{"5.15"}; | ||
48 | 1 | 100ns | $feature_bundle{"5.24"} = $feature_bundle{"5.23"}; | ||
49 | 1 | 100ns | $feature_bundle{"5.25"} = $feature_bundle{"5.23"}; | ||
50 | 1 | 100ns | $feature_bundle{"5.26"} = $feature_bundle{"5.23"}; | ||
51 | 1 | 100ns | $feature_bundle{"5.28"} = $feature_bundle{"5.27"}; | ||
52 | 1 | 100ns | $feature_bundle{"5.29"} = $feature_bundle{"5.27"}; | ||
53 | 1 | 100ns | $feature_bundle{"5.30"} = $feature_bundle{"5.27"}; | ||
54 | 1 | 100ns | $feature_bundle{"5.31"} = $feature_bundle{"5.27"}; | ||
55 | 1 | 100ns | $feature_bundle{"5.32"} = $feature_bundle{"5.27"}; | ||
56 | 1 | 600ns | $feature_bundle{"5.9.5"} = $feature_bundle{"5.10"}; | ||
57 | 1 | 700ns | my %noops = ( | ||
58 | postderef => 1, | ||||
59 | lexical_subs => 1, | ||||
60 | ); | ||||
61 | 1 | 200ns | my %removed = ( | ||
62 | array_base => 1, | ||||
63 | ); | ||||
64 | |||||
65 | 1 | 100ns | our $hint_shift = 26; | ||
66 | 1 | 0s | our $hint_mask = 0x1c000000; | ||
67 | 1 | 500ns | our @hint_bundles = qw( default 5.10 5.11 5.15 5.23 5.27 ); | ||
68 | |||||
69 | # This gets set (for now) in $^H as well as in %^H, | ||||
70 | # for runtime speed of the uc/lc/ucfirst/lcfirst functions. | ||||
71 | # See HINT_UNI_8_BIT in perl.h. | ||||
72 | 1 | 0s | our $hint_uni8bit = 0x00000800; | ||
73 | |||||
74 | # TODO: | ||||
75 | # - think about versioned features (use feature switch => 2) | ||||
76 | |||||
77 | =head1 NAME | ||||
78 | |||||
79 | feature - Perl pragma to enable new features | ||||
80 | |||||
81 | =head1 SYNOPSIS | ||||
82 | |||||
83 | use feature qw(say switch); | ||||
84 | given ($foo) { | ||||
85 | when (1) { say "\$foo == 1" } | ||||
86 | when ([2,3]) { say "\$foo == 2 || \$foo == 3" } | ||||
87 | when (/^a[bc]d$/) { say "\$foo eq 'abd' || \$foo eq 'acd'" } | ||||
88 | when ($_ > 100) { say "\$foo > 100" } | ||||
89 | default { say "None of the above" } | ||||
90 | } | ||||
91 | |||||
92 | use feature ':5.10'; # loads all features available in perl 5.10 | ||||
93 | |||||
94 | use v5.10; # implicitly loads :5.10 feature bundle | ||||
95 | |||||
96 | =head1 DESCRIPTION | ||||
97 | |||||
98 | It is usually impossible to add new syntax to Perl without breaking | ||||
99 | some existing programs. This pragma provides a way to minimize that | ||||
100 | risk. New syntactic constructs, or new semantic meanings to older | ||||
101 | constructs, can be enabled by C<use feature 'foo'>, and will be parsed | ||||
102 | only when the appropriate feature pragma is in scope. (Nevertheless, the | ||||
103 | C<CORE::> prefix provides access to all Perl keywords, regardless of this | ||||
104 | pragma.) | ||||
105 | |||||
106 | =head2 Lexical effect | ||||
107 | |||||
108 | Like other pragmas (C<use strict>, for example), features have a lexical | ||||
109 | effect. C<use feature qw(foo)> will only make the feature "foo" available | ||||
110 | from that point to the end of the enclosing block. | ||||
111 | |||||
112 | { | ||||
113 | use feature 'say'; | ||||
114 | say "say is available here"; | ||||
115 | } | ||||
116 | print "But not here.\n"; | ||||
117 | |||||
118 | =head2 C<no feature> | ||||
119 | |||||
120 | Features can also be turned off by using C<no feature "foo">. This too | ||||
121 | has lexical effect. | ||||
122 | |||||
123 | use feature 'say'; | ||||
124 | say "say is available here"; | ||||
125 | { | ||||
126 | no feature 'say'; | ||||
127 | print "But not here.\n"; | ||||
128 | } | ||||
129 | say "Yet it is here."; | ||||
130 | |||||
131 | C<no feature> with no features specified will reset to the default group. To | ||||
132 | disable I<all> features (an unusual request!) use C<no feature ':all'>. | ||||
133 | |||||
134 | =head1 AVAILABLE FEATURES | ||||
135 | |||||
136 | =head2 The 'say' feature | ||||
137 | |||||
138 | C<use feature 'say'> tells the compiler to enable the Perl 6 style | ||||
139 | C<say> function. | ||||
140 | |||||
141 | See L<perlfunc/say> for details. | ||||
142 | |||||
143 | This feature is available starting with Perl 5.10. | ||||
144 | |||||
145 | =head2 The 'state' feature | ||||
146 | |||||
147 | C<use feature 'state'> tells the compiler to enable C<state> | ||||
148 | variables. | ||||
149 | |||||
150 | See L<perlsub/"Persistent Private Variables"> for details. | ||||
151 | |||||
152 | This feature is available starting with Perl 5.10. | ||||
153 | |||||
154 | =head2 The 'switch' feature | ||||
155 | |||||
156 | B<WARNING>: Because the L<smartmatch operator|perlop/"Smartmatch Operator"> is | ||||
157 | experimental, Perl will warn when you use this feature, unless you have | ||||
158 | explicitly disabled the warning: | ||||
159 | |||||
160 | no warnings "experimental::smartmatch"; | ||||
161 | |||||
162 | C<use feature 'switch'> tells the compiler to enable the Perl 6 | ||||
163 | given/when construct. | ||||
164 | |||||
165 | See L<perlsyn/"Switch Statements"> for details. | ||||
166 | |||||
167 | This feature is available starting with Perl 5.10. | ||||
168 | |||||
169 | =head2 The 'unicode_strings' feature | ||||
170 | |||||
171 | C<use feature 'unicode_strings'> tells the compiler to use Unicode rules | ||||
172 | in all string operations executed within its scope (unless they are also | ||||
173 | within the scope of either C<use locale> or C<use bytes>). The same applies | ||||
174 | to all regular expressions compiled within the scope, even if executed outside | ||||
175 | it. It does not change the internal representation of strings, but only how | ||||
176 | they are interpreted. | ||||
177 | |||||
178 | C<no feature 'unicode_strings'> tells the compiler to use the traditional | ||||
179 | Perl rules wherein the native character set rules is used unless it is | ||||
180 | clear to Perl that Unicode is desired. This can lead to some surprises | ||||
181 | when the behavior suddenly changes. (See | ||||
182 | L<perlunicode/The "Unicode Bug"> for details.) For this reason, if you are | ||||
183 | potentially using Unicode in your program, the | ||||
184 | C<use feature 'unicode_strings'> subpragma is B<strongly> recommended. | ||||
185 | |||||
186 | This feature is available starting with Perl 5.12; was almost fully | ||||
187 | implemented in Perl 5.14; and extended in Perl 5.16 to cover C<quotemeta>; | ||||
188 | was extended further in Perl 5.26 to cover L<the range | ||||
189 | operator|perlop/Range Operators>; and was extended again in Perl 5.28 to | ||||
190 | cover L<special-cased whitespace splitting|perlfunc/split>. | ||||
191 | |||||
192 | =head2 The 'unicode_eval' and 'evalbytes' features | ||||
193 | |||||
194 | Together, these two features are intended to replace the legacy string | ||||
195 | C<eval> function, which behaves problematically in some instances. They are | ||||
196 | available starting with Perl 5.16, and are enabled by default by a | ||||
197 | S<C<use 5.16>> or higher declaration. | ||||
198 | |||||
199 | C<unicode_eval> changes the behavior of plain string C<eval> to work more | ||||
200 | consistently, especially in the Unicode world. Certain (mis)behaviors | ||||
201 | couldn't be changed without breaking some things that had come to rely on | ||||
202 | them, so the feature can be enabled and disabled. Details are at | ||||
203 | L<perlfunc/Under the "unicode_eval" feature>. | ||||
204 | |||||
205 | C<evalbytes> is like string C<eval>, but operating on a byte stream that is | ||||
206 | not UTF-8 encoded. Details are at L<perlfunc/evalbytes EXPR>. Without a | ||||
207 | S<C<use feature 'evalbytes'>> nor a S<C<use v5.16>> (or higher) declaration in | ||||
208 | the current scope, you can still access it by instead writing | ||||
209 | C<CORE::evalbytes>. | ||||
210 | |||||
211 | =head2 The 'current_sub' feature | ||||
212 | |||||
213 | This provides the C<__SUB__> token that returns a reference to the current | ||||
214 | subroutine or C<undef> outside of a subroutine. | ||||
215 | |||||
216 | This feature is available starting with Perl 5.16. | ||||
217 | |||||
218 | =head2 The 'array_base' feature | ||||
219 | |||||
220 | This feature supported the legacy C<$[> variable. See L<perlvar/$[>. | ||||
221 | It was on by default but disabled under C<use v5.16> (see | ||||
222 | L</IMPLICIT LOADING>, below) and unavailable since perl 5.30. | ||||
223 | |||||
224 | This feature is available under this name starting with Perl 5.16. In | ||||
225 | previous versions, it was simply on all the time, and this pragma knew | ||||
226 | nothing about it. | ||||
227 | |||||
228 | =head2 The 'fc' feature | ||||
229 | |||||
230 | C<use feature 'fc'> tells the compiler to enable the C<fc> function, | ||||
231 | which implements Unicode casefolding. | ||||
232 | |||||
233 | See L<perlfunc/fc> for details. | ||||
234 | |||||
235 | This feature is available from Perl 5.16 onwards. | ||||
236 | |||||
237 | =head2 The 'lexical_subs' feature | ||||
238 | |||||
239 | In Perl versions prior to 5.26, this feature enabled | ||||
240 | declaration of subroutines via C<my sub foo>, C<state sub foo> | ||||
241 | and C<our sub foo> syntax. See L<perlsub/Lexical Subroutines> for details. | ||||
242 | |||||
243 | This feature is available from Perl 5.18 onwards. From Perl 5.18 to 5.24, | ||||
244 | it was classed as experimental, and Perl emitted a warning for its | ||||
245 | usage, except when explicitly disabled: | ||||
246 | |||||
247 | no warnings "experimental::lexical_subs"; | ||||
248 | |||||
249 | As of Perl 5.26, use of this feature no longer triggers a warning, though | ||||
250 | the C<experimental::lexical_subs> warning category still exists (for | ||||
251 | compatibility with code that disables it). In addition, this syntax is | ||||
252 | not only no longer experimental, but it is enabled for all Perl code, | ||||
253 | regardless of what feature declarations are in scope. | ||||
254 | |||||
255 | =head2 The 'postderef' and 'postderef_qq' features | ||||
256 | |||||
257 | The 'postderef_qq' feature extends the applicability of L<postfix | ||||
258 | dereference syntax|perlref/Postfix Dereference Syntax> so that postfix array | ||||
259 | and scalar dereference are available in double-quotish interpolations. For | ||||
260 | example, it makes the following two statements equivalent: | ||||
261 | |||||
262 | my $s = "[@{ $h->{a} }]"; | ||||
263 | my $s = "[$h->{a}->@*]"; | ||||
264 | |||||
265 | This feature is available from Perl 5.20 onwards. In Perl 5.20 and 5.22, it | ||||
266 | was classed as experimental, and Perl emitted a warning for its | ||||
267 | usage, except when explicitly disabled: | ||||
268 | |||||
269 | no warnings "experimental::postderef"; | ||||
270 | |||||
271 | As of Perl 5.24, use of this feature no longer triggers a warning, though | ||||
272 | the C<experimental::postderef> warning category still exists (for | ||||
273 | compatibility with code that disables it). | ||||
274 | |||||
275 | The 'postderef' feature was used in Perl 5.20 and Perl 5.22 to enable | ||||
276 | postfix dereference syntax outside double-quotish interpolations. In those | ||||
277 | versions, using it triggered the C<experimental::postderef> warning in the | ||||
278 | same way as the 'postderef_qq' feature did. As of Perl 5.24, this syntax is | ||||
279 | not only no longer experimental, but it is enabled for all Perl code, | ||||
280 | regardless of what feature declarations are in scope. | ||||
281 | |||||
282 | =head2 The 'signatures' feature | ||||
283 | |||||
284 | B<WARNING>: This feature is still experimental and the implementation may | ||||
285 | change in future versions of Perl. For this reason, Perl will | ||||
286 | warn when you use the feature, unless you have explicitly disabled the | ||||
287 | warning: | ||||
288 | |||||
289 | no warnings "experimental::signatures"; | ||||
290 | |||||
291 | This enables unpacking of subroutine arguments into lexical variables | ||||
292 | by syntax such as | ||||
293 | |||||
294 | sub foo ($left, $right) { | ||||
295 | return $left + $right; | ||||
296 | } | ||||
297 | |||||
298 | See L<perlsub/Signatures> for details. | ||||
299 | |||||
300 | This feature is available from Perl 5.20 onwards. | ||||
301 | |||||
302 | =head2 The 'refaliasing' feature | ||||
303 | |||||
304 | B<WARNING>: This feature is still experimental and the implementation may | ||||
305 | change in future versions of Perl. For this reason, Perl will | ||||
306 | warn when you use the feature, unless you have explicitly disabled the | ||||
307 | warning: | ||||
308 | |||||
309 | no warnings "experimental::refaliasing"; | ||||
310 | |||||
311 | This enables aliasing via assignment to references: | ||||
312 | |||||
313 | \$a = \$b; # $a and $b now point to the same scalar | ||||
314 | \@a = \@b; # to the same array | ||||
315 | \%a = \%b; | ||||
316 | \&a = \&b; | ||||
317 | foreach \%hash (@array_of_hash_refs) { | ||||
318 | ... | ||||
319 | } | ||||
320 | |||||
321 | See L<perlref/Assigning to References> for details. | ||||
322 | |||||
323 | This feature is available from Perl 5.22 onwards. | ||||
324 | |||||
325 | =head2 The 'bitwise' feature | ||||
326 | |||||
327 | This makes the four standard bitwise operators (C<& | ^ ~>) treat their | ||||
328 | operands consistently as numbers, and introduces four new dotted operators | ||||
329 | (C<&. |. ^. ~.>) that treat their operands consistently as strings. The | ||||
330 | same applies to the assignment variants (C<&= |= ^= &.= |.= ^.=>). | ||||
331 | |||||
332 | See L<perlop/Bitwise String Operators> for details. | ||||
333 | |||||
334 | This feature is available from Perl 5.22 onwards. Starting in Perl 5.28, | ||||
335 | C<use v5.28> will enable the feature. Before 5.28, it was still | ||||
336 | experimental and would emit a warning in the "experimental::bitwise" | ||||
337 | category. | ||||
338 | |||||
339 | =head2 The 'declared_refs' feature | ||||
340 | |||||
341 | B<WARNING>: This feature is still experimental and the implementation may | ||||
342 | change in future versions of Perl. For this reason, Perl will | ||||
343 | warn when you use the feature, unless you have explicitly disabled the | ||||
344 | warning: | ||||
345 | |||||
346 | no warnings "experimental::declared_refs"; | ||||
347 | |||||
348 | This allows a reference to a variable to be declared with C<my>, C<state>, | ||||
349 | our C<our>, or localized with C<local>. It is intended mainly for use in | ||||
350 | conjunction with the "refaliasing" feature. See L<perlref/Declaring a | ||||
351 | Reference to a Variable> for examples. | ||||
352 | |||||
353 | This feature is available from Perl 5.26 onwards. | ||||
354 | |||||
355 | =head2 The 'isa' feature | ||||
356 | |||||
357 | This allows the use of the C<isa> infix operator, which tests whether the | ||||
358 | scalar given by the left operand is an object of the class given by the | ||||
359 | right operand. See L<perlop/Class Instance Operator> for more details. | ||||
360 | |||||
361 | This feature is available from Perl 5.32 onwards. | ||||
362 | |||||
363 | =head2 The 'indirect' feature | ||||
364 | |||||
365 | This feature allows the use of L<indirect object | ||||
366 | syntax|perlobj/Indirect Object Syntax> for method calls, e.g. C<new | ||||
367 | Foo 1, 2;>. It is enabled by default, but can be turned off to | ||||
368 | disallow indirect object syntax. | ||||
369 | |||||
370 | This feature is available under this name from Perl 5.32 onwards. In | ||||
371 | previous versions, it was simply on all the time. To disallow (or | ||||
372 | warn on) indirect object syntax on older Perls, see the L<indirect> | ||||
373 | CPAN module. | ||||
374 | |||||
375 | =head1 FEATURE BUNDLES | ||||
376 | |||||
377 | It's possible to load multiple features together, using | ||||
378 | a I<feature bundle>. The name of a feature bundle is prefixed with | ||||
379 | a colon, to distinguish it from an actual feature. | ||||
380 | |||||
381 | use feature ":5.10"; | ||||
382 | |||||
383 | The following feature bundles are available: | ||||
384 | |||||
385 | bundle features included | ||||
386 | --------- ----------------- | ||||
387 | :default indirect | ||||
388 | |||||
389 | :5.10 say state switch indirect | ||||
390 | |||||
391 | :5.12 say state switch unicode_strings indirect | ||||
392 | |||||
393 | :5.14 say state switch unicode_strings indirect | ||||
394 | |||||
395 | :5.16 say state switch unicode_strings | ||||
396 | unicode_eval evalbytes current_sub fc | ||||
397 | indirect | ||||
398 | |||||
399 | :5.18 say state switch unicode_strings | ||||
400 | unicode_eval evalbytes current_sub fc | ||||
401 | indirect | ||||
402 | |||||
403 | :5.20 say state switch unicode_strings | ||||
404 | unicode_eval evalbytes current_sub fc | ||||
405 | indirect | ||||
406 | |||||
407 | :5.22 say state switch unicode_strings | ||||
408 | unicode_eval evalbytes current_sub fc | ||||
409 | indirect | ||||
410 | |||||
411 | :5.24 say state switch unicode_strings | ||||
412 | unicode_eval evalbytes current_sub fc | ||||
413 | postderef_qq indirect | ||||
414 | |||||
415 | :5.26 say state switch unicode_strings | ||||
416 | unicode_eval evalbytes current_sub fc | ||||
417 | postderef_qq indirect | ||||
418 | |||||
419 | :5.28 say state switch unicode_strings | ||||
420 | unicode_eval evalbytes current_sub fc | ||||
421 | postderef_qq bitwise indirect | ||||
422 | |||||
423 | :5.30 say state switch unicode_strings | ||||
424 | unicode_eval evalbytes current_sub fc | ||||
425 | postderef_qq bitwise indirect | ||||
426 | |||||
427 | :5.32 say state switch unicode_strings | ||||
428 | unicode_eval evalbytes current_sub fc | ||||
429 | postderef_qq bitwise indirect | ||||
430 | |||||
431 | The C<:default> bundle represents the feature set that is enabled before | ||||
432 | any C<use feature> or C<no feature> declaration. | ||||
433 | |||||
434 | Specifying sub-versions such as the C<0> in C<5.14.0> in feature bundles has | ||||
435 | no effect. Feature bundles are guaranteed to be the same for all sub-versions. | ||||
436 | |||||
437 | use feature ":5.14.0"; # same as ":5.14" | ||||
438 | use feature ":5.14.1"; # same as ":5.14" | ||||
439 | |||||
440 | =head1 IMPLICIT LOADING | ||||
441 | |||||
442 | Instead of loading feature bundles by name, it is easier to let Perl do | ||||
443 | implicit loading of a feature bundle for you. | ||||
444 | |||||
445 | There are two ways to load the C<feature> pragma implicitly: | ||||
446 | |||||
447 | =over 4 | ||||
448 | |||||
449 | =item * | ||||
450 | |||||
451 | By using the C<-E> switch on the Perl command-line instead of C<-e>. | ||||
452 | That will enable the feature bundle for that version of Perl in the | ||||
453 | main compilation unit (that is, the one-liner that follows C<-E>). | ||||
454 | |||||
455 | =item * | ||||
456 | |||||
457 | By explicitly requiring a minimum Perl version number for your program, with | ||||
458 | the C<use VERSION> construct. That is, | ||||
459 | |||||
460 | use v5.10.0; | ||||
461 | |||||
462 | will do an implicit | ||||
463 | |||||
464 | no feature ':all'; | ||||
465 | use feature ':5.10'; | ||||
466 | |||||
467 | and so on. Note how the trailing sub-version | ||||
468 | is automatically stripped from the | ||||
469 | version. | ||||
470 | |||||
471 | But to avoid portability warnings (see L<perlfunc/use>), you may prefer: | ||||
472 | |||||
473 | use 5.010; | ||||
474 | |||||
475 | with the same effect. | ||||
476 | |||||
477 | If the required version is older than Perl 5.10, the ":default" feature | ||||
478 | bundle is automatically loaded instead. | ||||
479 | |||||
480 | Unlike C<use feature ":5.12">, saying C<use v5.12> (or any higher version) | ||||
481 | also does the equivalent of C<use strict>; see L<perlfunc/use> for details. | ||||
482 | |||||
483 | =back | ||||
484 | |||||
485 | =cut | ||||
486 | |||||
487 | # spent 24µs (2+22) within feature::import which was called:
# once (2µs+22µs) by experimental::_enable at line 61 of experimental.pm | ||||
488 | 1 | 100ns | shift; | ||
489 | |||||
490 | 1 | 100ns | if (!@_) { | ||
491 | croak("No features specified"); | ||||
492 | } | ||||
493 | |||||
494 | 1 | 2µs | 1 | 22µs | __common(1, @_); # spent 22µs making 1 call to feature::__common |
495 | } | ||||
496 | |||||
497 | sub unimport { | ||||
498 | shift; | ||||
499 | |||||
500 | # A bare C<no feature> should reset to the default bundle | ||||
501 | if (!@_) { | ||||
502 | $^H &= ~($hint_uni8bit|$hint_mask); | ||||
503 | return; | ||||
504 | } | ||||
505 | |||||
506 | __common(0, @_); | ||||
507 | } | ||||
508 | |||||
509 | |||||
510 | # spent 22µs within feature::__common which was called:
# once (22µs+0s) by feature::import at line 494 | ||||
511 | 1 | 200ns | my $import = shift; | ||
512 | 1 | 400ns | my $bundle_number = $^H & $hint_mask; | ||
513 | my $features = $bundle_number != $hint_mask | ||||
514 | 1 | 500ns | && $feature_bundle{$hint_bundles[$bundle_number >> $hint_shift]}; | ||
515 | 1 | 200ns | if ($features) { | ||
516 | # Features are enabled implicitly via bundle hints. | ||||
517 | # Delete any keys that may be left over from last time. | ||||
518 | 1 | 8µs | delete @^H{ values(%feature) }; | ||
519 | 1 | 400ns | $^H |= $hint_mask; | ||
520 | 1 | 300ns | for (@$features) { | ||
521 | 11 | 7µs | $^H{$feature{$_}} = 1; | ||
522 | 11 | 1µs | $^H |= $hint_uni8bit if $_ eq 'unicode_strings'; | ||
523 | } | ||||
524 | } | ||||
525 | 1 | 2µs | while (@_) { | ||
526 | 1 | 100ns | my $name = shift; | ||
527 | 1 | 1µs | if (substr($name, 0, 1) eq ":") { | ||
528 | my $v = substr($name, 1); | ||||
529 | if (!exists $feature_bundle{$v}) { | ||||
530 | $v =~ s/^([0-9]+)\.([0-9]+).[0-9]+$/$1.$2/; | ||||
531 | if (!exists $feature_bundle{$v}) { | ||||
532 | unknown_feature_bundle(substr($name, 1)); | ||||
533 | } | ||||
534 | } | ||||
535 | unshift @_, @{$feature_bundle{$v}}; | ||||
536 | next; | ||||
537 | } | ||||
538 | 1 | 100ns | if (!exists $feature{$name}) { | ||
539 | if (exists $noops{$name}) { | ||||
540 | next; | ||||
541 | } | ||||
542 | if (!$import && exists $removed{$name}) { | ||||
543 | next; | ||||
544 | } | ||||
545 | unknown_feature($name); | ||||
546 | } | ||||
547 | 1 | 400ns | if ($import) { | ||
548 | 1 | 700ns | $^H{$feature{$name}} = 1; | ||
549 | 1 | 100ns | $^H |= $hint_uni8bit if $name eq 'unicode_strings'; | ||
550 | } else { | ||||
551 | delete $^H{$feature{$name}}; | ||||
552 | $^H &= ~ $hint_uni8bit if $name eq 'unicode_strings'; | ||||
553 | } | ||||
554 | } | ||||
555 | } | ||||
556 | |||||
557 | sub unknown_feature { | ||||
558 | my $feature = shift; | ||||
559 | croak(sprintf('Feature "%s" is not supported by Perl %vd', | ||||
560 | $feature, $^V)); | ||||
561 | } | ||||
562 | |||||
563 | sub unknown_feature_bundle { | ||||
564 | my $feature = shift; | ||||
565 | croak(sprintf('Feature bundle "%s" is not supported by Perl %vd', | ||||
566 | $feature, $^V)); | ||||
567 | } | ||||
568 | |||||
569 | sub croak { | ||||
570 | require Carp; | ||||
571 | Carp::croak(@_); | ||||
572 | } | ||||
573 | |||||
574 | 1 | 11µs | 1; | ||
575 | |||||
576 | # ex: set ro: |